J. Phys. IV France 09 (1999) Pr9-165-Pr9-173
Regular features of the evolutionary behaviour exhibited by plastic flow localisation and fracture in metals and alloysL.B. Zuev, V.I. Danilov, S.Yu. Zavodchikov and S.A. Barannikova
Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, Tomsk 634021, Russia
Considered is the generation of self-excited waves by non-homogeneous plastic flow observed for a range of alloys in a single-crystal and a polycrystalline state at the stage of linear work hardening. It is found that under such conditions, in plastically deforming single austenitic crystals and polycrystalline Zr base alloys there originate self-excited waves propagating in the material volume at a rate of ~ 10-5 m/s. It turns out that the motion velocity of self-excited waves is inversely proportional to the extent of work hardening, which sets them apart from the well-known plasticity waves. The effect of extension axis orientation on the kinetic parameters of self-excited waves observable in the single crystals tested has been examined. Plastic flow is regarded as a self-organization process occurring in a deforming medium, and the universality of the proposed approach to the description of plastic flow is substantiated. The evolution of self-excited waves in the deforming alloys during material's transition to parabolic work hardening and on to fracture is described.
© EDP Sciences 1999